The present invention pertains to power tools; more particularly, the present invention pertains to hand held power tools such as screwdrivers or nutdrivers.
In recent years the down sizing of motors, gear boxes, and battery packs, has allowed the placement of batteries, motors, and gear boxes in the handles of hand held power tools. One common example is a power screwdriver. Such power screwdrivers have become readily available and great aids to construction workers and repairmen.
While hand held power screwdrivers are convenient, extended use of these power screwdrivers has surfaced some needs to make the power screwdriver more user friendly. The first of these needs is a reduction in the extended length normally found in power screwdrivers. Most power screwdriver manufacturers have found that tool handles must be made long to contain the battery, the motor, and the gear box. This handle length is increased even further by the placement of a switch mechanism between the battery and motor or anywhere along the central axis of the tool to control both the flow of electricity and the rotational direction of the motor. Extended handle length reduces usability of the power screwdriver in small spaces. Additionally, the farther back on the handle the switch is placed, the further back on the handle the tool is held. Unfortunately, such hand position diminishes control of the power tool.
There is a need to shorten the handles of power screwdrivers to overcome the foregoing problems. Such shortening should include placing the "on-off" and directional control switches as far forward as possible so that the operator need not re-position the hand when operating the power screwdriver.
Secondly, most power screwdrivers are generally cylindrical. For single-use, infrequent operation, a cylindrical configuration may be satisfactory. But, for the professional user, the cylindrical shape creates undue muscle strain as the space created in the human hand when an operator curls fingers around a tool is not cylindrical, but conical. There is, therefore, a need to shape the handle of a power screwdriver more like the opening formed in a human hand when it encircles a tool and to provide adequate resistance to torque so the tool does not turn in the hand.
Third, most power screwdrivers have generally smooth or lightly textured surfaces. For low-torque applications, such surfaces may be entirely satisfactory. For high torque applications or applications where the user's grip has been weakened by a disease, such as Carpal Tunnel Syndrome, there is a need to enhance the user's ability to grip the power screwdriver handle.
There is, therefore, a need in the art to provide a power tool handle that has a shortened handle with easily accessible operating controls, a shape conforming to the user's hand and a surface which is easy to grip even in high torque situations.